spark from coil, but not from distributor

I have a 1998 golf gti, im getting spark from the coil, but not from the distributor i have
checked or replaced the following items. replaced ignition plug, replaced the coil,
checked the wire from the coil to the distributor, replaced the distributor, roter and cap
twice. roter turns. i have canceled out timing because the car was fine and just
suddenly did not want to start. IT starts intermediately maybe one in 50 tries and once it
starts it idles, revs like normal, but if i switch it of it wont start again. connected 24volts,
tried a better earth still nothing. i have had two very experienced mechanics look at it
and both came to the not getting spark at distributer conclusion by them selves. we
turned a distributor in our hand inside the cap and the computer box is firing the
injectors as you turn the distributor. we hot wired it at the starter to bypass the ignition. I
think thats it. any ideas?